Drying apparatus



June 27, 1950 G. SCHWIETERT DRYING APPARATUS Filed Dec. '7, 1946 Patented June 27, 1950 UNITED STATES PATENT OFFICE Gustav Schwietert, McGregor, Iowa Application December 7, 1946, Serial No. 714,800

This invention relates to drying apparatus and to a method of drying. The invention is particularly useful in the drying of grain, hay, and other materials from which moisture should be removed.

An object of the invention is to provide apparatus and method steps enabling grain, hay, and other materials to be efiectively dried at relatively low temperatures andwhile producing a final product of unusually high quality. A further object is to provide means and method steps whereby the direct rays of a heating medium, including infra-red and ultra-violet rays, are caused to impinge directly upon theproduct being dried and in which a rotating heated body of air is caused to traverse the zone in which the materials are being dried; Yet another ob ject is to provide a heating zone in which material to be dried is rotated while being maintained under partial vacuum and at relatively low temperatures. Yet another object is to provide mechanism in which material to be dried is rotated in contact with heated air and under a partial vacuum and then passed through a suction zone and into a pressure-separating zone from which the material is drawn with a cooling current of air into a second collecting zone. Yet another object is to provide effective means for distributing the material being dried uniformly throughout a heating zone so as to effectively contact the material with the incoming heated air. Other specific objects and advantages will appear as the specification proceeds.

The invention is illustrated,'in a preferred embodiment, by the accompanying drawing, in which Figure 1 is a broken longitudinal sectional view of apparatus embodying my invention; and Fig. 2, a 'broken transverse sectional view, the section being taken as indicated at line 2-2 of Fig. 1.

In the illustration given, In designates a drying cylinder which may be circular in'cross section or of any other desired contour. The cylinder is provided with reinforcing rings II and toward its ends with bearing rings [2. The hearing rings l2 rest upon anti-friction rollers l3 supported in trunnions M. The shaft of one of the rollers I3 is extended and is provided with a gear l5 meshing with a drive'gear l6. Thedrive gear I6 is mounted upon the shaft l1 and at the other end of the shaft I1 is mounted a gear l8. It will be understood that the shaft I1 is driven by any suitable power means. The trunnions ll of rollers I3 are supported upon the base l9.

3 Claims. (Cl. 263-32) At the lefthand side of the cylinder I0 is a heater casing which provides air inlet passages 2| and a combustion chamber 22. A fuel pipe '23 for oil or any suitable heating fluid passes into the chamber 22 and is discharged through a nozzle 24. Curved vanes 25 direct the incoming preheated air about the nozzle 24 so as to cause the air to rotate within the chamber 22. 'Fire brick 26 is supported about the nozzle 24 and, if desired, may be extended about the entire or most of the chamber 22. The stationary casing 20 preferably carries a ring flange member 21 which extends over and forms a relatively tight joint with the rotatable casing ID.

The stationary casing 20 is also provided with a chute 28 entering through the top or side wall of the casing 20 and discharging through the outlet 29 into the interior of cylinder It]. It will be understood that any suitable means, such as, for example, an endless chain conveyor, may be employed for carrying grain or other material upwardly and discharging the same into the open end of the chute 28; or, if desired, the material may be introduced by hand or by any other means into the chute.

The cylinder [0 is provided on its inner side with a plurality of fins 30 extending in parallel and longitudinally of the cylinder. I also prefer to provide fins 3| spaced about the cylinder and provided with forwardly-extending distributor ledges 32. The ledges 32 serve to hold a portion of the grain, alfalfa, or other material upon the fin and to release it gradually as the cylinder rotates, thus producing a relatively uniform distribution of the material to be dried across the interior of the cylinder.

' Near the exit end of the cylinder I0, I provide a fixed baffle 33 which extends between the fins 3D and 3| and completely closes off the central portion of the cylinder l0, thus causing the material to be brought to pass around the battle 33 and along the fins 30 and 3|.

The cylinder I0 is provided at its exit end with a closure plate 34 having an outlet aperture 35. In front of the aperture 35 I provide a baffle plate 36fixed to and upon a rotatably-mounted baflle gear 31 so that the baffie may be moved to various positions by the dotted lines 38. The position of the gear 31 is controlled by the bevel gear39 mounted upon control shaft 40. The shaft 49 is rotatably mounted within the sleeve 4| mounted upon bracket 42. The shaft 40 is'provided with a removable control handle. Communicating with the outlet 35 of cylinder l Dis a fan casing 43 providing a fan chamber 44.

A shaft 45 extends into the chamber 44 and supports the fan 46. From the fan casing 43 extends a duct 4'! and the duct leads to a separator cone or chamber 48. The chamber 48 may be provided of any suitable type of casing and may be of any suitable shape. I prefer to employ a casing providing a top chamber having a frusto-conical bot tom portion 69 leading to an outlet 50. Preferably, the chamber is provided at its top with an upwardly-extending. portion 5i having a vapor outlet at its top." If desired, the vapor outlet maybe provided with a cone cap or any other suitable type of cap. The outlet portion 50 of the chamber 48 communicates with a duct 52provided depending upon the type of material employed and that such variance can be efiectively controlled through the rotatable baflle 36 controlled by shaft 40. By moving the bafiie to a position in parallel with the member 40, there is a minimum of resistance to air flow, while the resistance i increased as the baflle is moved toward the transverse position illustrated in Fig. 1.

After the material has passed through the cylindfe'r 'l!) and" dischargdzinto the fan chamber under the influence of'suction, the'fan 46 then moves the material outwardly under pressure through duct 41 to the separating chamber 48. Here, the vapors are free to discharge through the upwardly-extending outlet 5| while the grain or other material drops downwardly toward the to any desired point of destination. For example;

the cooled material may be discharged into a second conical separator. similar 'to chamber &8; and provided with a vapor outlet, the grain or other dried material being discharged through thelower portion of the separatoriinto' a hammer mill on in any desired receptacle. It is sufiicient-to-show the passing of the materialwithits cool charge of -air through duct 55 which maylea dto any desired destination for further treatment or storage. I

The=shaft45 controlling the two fans maybe driven by any suitable power source, In the illustration g iven, a drive chain Sit-connects; the sprocket gear is and the gearr fill on shaft 45.

Operation "In the operation f the device, grain, alfalfa, or any other desired material to be dried is' in troduced through the 'chute 28 into the interior of cylinder it. Gaseous or liquidfuel isintroduced through line 123 and atomizer head 24 and ignited Within'th'e combustion chamber 22. Air passes through the inlets 2! about the combustion chamber fi where it is preheated and finally is dis charged by the vanes "25' in a rotating annulus about the combustion chamber. The'air thus 4 heated is'dire'cted toward the interior'of casing I 0. Since there is no partition wall'between the open combustion chamber 22 and the interior'of casing Hi, the air flows forwardly in it's rotationalfform into the cylinder, while atth'e same time the' rays of-the 'burning gases, including the infra-red and ultra-violet rays, impinge directly .upon'the produdts'being dried,

The cylinder m is maintained in rotation by the drive shaft l'l'throtugh gears I6 and I5 and the fins 3t. and Si constantly liftth'ematerialas itipasses through the cylinder and discharge it within the interior of the cylinder. The fins 3i, ivith'their distribution ledges 32, effectively carry and gradually release the material tobe dried as the cylinderrotates. It will beunderstood that the ledges 32 may be made shorter orlon'ger in order to adapt them to any particular'type' of material being dried.

solids outlet 50. At the point of discharge 50, fresh and cool air is drawn through the opening '53andyunder the influence of the fan in chamber 54, the solids are drawnwith the cooling medium through-duct -52 and thence through chambeu fl. The material isthen discharged through duct 55 into any further separating or treating structures or to-any desired destination.

It will be noted that the above relatively simple and compactapparatusresultsin the removal of moisture from, the material and while the sameis maintained under partial vacuum, while permit.- ting under a pressure zone the. removal of vapors and-the cooling of the solids through the intake of fresh air. v

I have; found that beneficial effects upon the drying. material,suehas-grain, hay, etc, are produced throughthe exposure thereof to the direct rays of the fiamein. the combustion chamber, and furtherthatmore-efiective drying is produced bytaking theuheatedandrotating gasesin the combustion .chamber directly into the rotating cylinder ill, I I

I have foundthat bymaintaining. the cylinder it under partial vacuum that effective drying-is produced at 'relativelylow temperatures which donot scorch Orin any way damage the product. By maintaining. .thepressure. below atmospheric, the drying operation can be effectively carried out with large volume while maintainingthe temperature slightly below the boiling point of Water or in the neighborhood of this temperature. Fairly satisfactory drying has been produced when the temperature at the inlet and of. the drying chamber is maintained in the'range of 210 215: F. It will be noted thatthe single fan 46 is effective as a suction-producing instrument forcontrolling the interior of cylinder mwhile at the-sametimeit is effective as a pressure means for discharging the material through duct 4-1 into the separating chamber. I-Iere', vaporsare liberated and the dried g-rainpr other solids-drop downwardly. to :a nou-tlet point wherethey are picked up by. avolumeof fresh air. The freshaaij-r serves as a means for conveying the grain or other solids and also as a means :for cooling the'sameas it, is dischargedrtowardthe next treating operadicated in dotted lines in the drawing, enables heavy weight grains, such as corn and beans, too heavy to be lifted by air, into the exhaust fan.

The drying apparatus is useful not only in the drying of grain, alfalfa, and other types .of crops, but also in the drying of many other objects and materials not herein listed.

While in the foregoing specification, I have set forth in considerable detail specific apparatus and process steps as illustrative of the invention, it will be understood that such details may be varied widely by those skilled in the art without departing from the spirit of my invention.

I claim:

1. In drying apparatus, a stationary casing providing a combustion chamber, means for introducing fuel into said combustion chamber for burning, vanes supported about said fuel line, means for introducing air against said vanes to produce a rotating body of gas within said combustion chamber, a frame, a cylindrical casing communicating at one end with said combustion chamber and supported in said frame for rotation, a fixed end plate closing the other end of said cylinder and equipped centrally with an outlet opening, fins within said casing extending 1ongitudinally thereof, an inlet chute for directing material to be dried directly into the open end of said cylindrical casing, baffles extending centrally across said cylindrical casing but spaced from the inner walls of said casing, means for rotating said casing, a conduit communicating with the outlet opening of said end plate, and means for producing subatmospheric pressure within said conduit.

2. In drying apparatus, a frame, a cylindrical casing mounted in said frame for rotation, a stationary casing, closed at one end and communicating at its other end with the open end of said first-mentioned casing, means for injecting fuel into said stationary casing, means for supplying air to said stationary casing, deflector vanes for rotating said incoming air, fins extending longitudinally of said cylindrical casing for arresting rotary movement of said air, means for introducing material to be dried into the open end portion of said rotating casing, an end plate closing the end of the casing opposite said stationary casing, said end plate being equipped with an outlet opening, and a fan-equipped exhaust conduit communicating with said end plate openmg.

3. In drying apparatus, a frame, a cylindrical casing mounted in said frame for rotation, a stationary casing closed at one end and communicating at its other end with the open end of said first-mentioned casing, means for injecting fuel and air into said stationary casing, deflector vanes for rotating said air, means for arresting the rotation of said air within said cylindrical casing and comprising longitudinally-extending fins extending inwardly from the cylindrical casing and terminating to provide a free central passage, a baflle extending centrally across the cylindrical casing near the end thereof opposite said stationary casin but spaced inwardly from the inner walls of said casing, an end plate closing the end of the casing opposite said fixed casing and provided with a central discharge opening, a fan equipped exhaust conduit communicating with said end plate opening, and means for introducing material to be dried into the end of said cylindrical casing adjacent said stationary casing.

GUSTAV SCHWIE'I'ERT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 486,806 Batcheller Nov. 22, 1892 534,491 Atwood Feb. 29, 1895 748,893 Trump Jan. 5, 1904 748,894 Trump Jan. 5, 1904 1,238,394 Eldred Aug. 28, 1917 1,477,823 Grindle Dec. 18, 1923 1,703,635 Ranson Feb. 26, 1929 1,800,247 Buckbee Apr. 14, 1931 1,988,677 Arnold Jan. 22, 1935 1,988,678 Arnold Jan. 22, 1935 2,000,733 Avery May 7, 1935 2,070,227 Essers Feb. 9, 1937 2,276,589 Peltier et al. Mar. 17, 1942 2,319,673 French May 18, 1943 2,319,674 French et a1 May 18, 1943 2,341,101 Howard Feb. 8, 1944 

